One of the modules in a bonding machine for electronic devices, such as a die bonding machine, is the bond head. During a bonding process, an electronic device is first placed onto a collet of the bond head. The collet is then heated to about 350 degrees Celsius using a heater assembled in the bond head. Such heating melts the solder balls attached with the electronic device and while the solder balls are melted, the electronic device is urged against a bonding site, such as a substrate, with a predetermined force. As a result, the electronic device is bonded with the substrate via the melted solder balls. To strengthen this bond, the solder balls are cooled so that they can solidify and harden. It is beneficial to heat and cool the solder balls as quickly as possible so as to increase bond quality and productivity.
Conventional methods of increasing the heating rate include pulse heating, whereas conventional methods of increasing the cooling rate include actively cooling the bond head heater by blowing compressed gas or passing liquid through cooling channels inside the bond head. However, even with such active cooling of the bond head heater, the cooling rate remains unsatisfactory.
To further increase the cooling rate of the solder balls, US Patent Publication Number 2016/0116217A1 describes a bond head having a plurality of spray nozzles inside it. More specifically, the spray nozzles are positioned below the heater of the bond head. To cool the heater, a water spray is generated and is directed at the bottom surface of the heater via each of the spray nozzles. However, it is difficult to install the spray nozzles in bond heads which are small in size and which have small heaters (e.g. heaters which are less than 16 mm×16 mm in size). Therefore, the bond head has to be relatively large in order to accommodate the spray nozzles. Further, due to the tiny openings of the spray nozzles, the amount of water spray that can be generated and directed at the heater is limited.